Means for delaying the arming of a projectile



April 4, 1956 H. H. DERINGER 2,

MEANS FOR DELAYING THE ARMING OF A PROJECTILE Filed Feb. 11, 1946 2 Sheets-Sheet 1 1?. H Dari)" April 1956 H. H. DERINGER 2,742,858

MEANS FOR DELAYING THE ARMING OF A PROJECTILE 2 Filed Feb. 11, 1946 2 Sheets-Sheet 2 i FY% 3. H 4.

34 35 36 IS a 34 35 3s 19 1 16i; 5. Flag 6 3g 35? 3 19 k k 22 4| gg X X*/ 43A 37 49 Gamma;

United States Patent MEANS FOR DELAYING THE ARMING OF A PROJECTILE Harry H. Deringer, United States Navy, Chestertown, Md.

Application February 11, 1946, Serial No. 646,941

7 Claims. (Cl. 102-79) (Granted under Title 35, U. S. Code (1952), sec. 266) This invention relates to a safety base fuze for a projectile and more particularly to a fuze for use with a projectile preferably employing the usual nose fuze and adapted to be fired from a gun, the fuze of the present invention being provided with a firing pin adapted to be struck by a percussion cap with suflicient force to explode an explosive charge within the projectile as the projectile strikes the target, in which the percussion cap is locked in a safe position by a pair of inertia detents until the projectile is clear of the gun and the force of the acceleration thereof has diminished to a predetermined value.

In devices of this character heretofore devised for preventing the premature explosion of the projectile in or within the vicinity of the gun as the gun is fired, it has been the usual practice to employ a pair of cylindrical detents adapted to be moved outwardly Within radially disposed tubular apertures within the projectile and thereby remove a restraint from the firing pin and cause the projectile to be armed as the detents move outwardly to an unlocked position by the centrifugal force acting thereon in response to the forcing of the projectile through the bore of the gunby the explosion of the main explosive charge. In the event that the detents should be moved to the unlocked position before the projectile "has traveled beyond the muzzle of the gun, the force of acceleration acting on the inertial plunger member may cause the plunger to strike the firing pin with su'fiicient force to explode the projectile while the projectile is still within the barrel of the gun thereby damaging or destroying the gun and causing casualties to the gun crew and other personnel within the vicinity of the gun.

The force resulting from the acceleration of the projectile in response to the expansion of the gases within the gun is applied 'in a direction along the path of travel of the projectile and is herein referred to as a setback force. This setback force decays rapidly as the projectile leaves the muzzle of the gun and attains zero value when the maximum velocity of the projectile is reached.

In accordance with the present invention this difficulty is overcome by employing a pair of locking detents in which the setback force applied thereto as the gun is fired causes each of the detents to engage a plurality of cam surfaces diametrically arranged in staggered spaced relation inter'iorly of a fixed annular member within which the detent is adapted to move by the action of centrifugal force applied thereto by the rotation of the projectile whereby a plunger supporting the percussion cap remains locked in 'a safe position until the detents have moved to an armed or unlocked position during the flight of the projectile along a trajectory.

One of the objects of the present invention is the provision of new and improved means for preventing the premature firing of an explosive charge within a projectile during the transportation, handling, loading and firing of the projectile from a gun in which the projectile is armed during the flight and remains ar'med until the projectile explodes upon impact with'thetarget.

Another of the objects is to provide new and improved means for maintaining the inertial plunger of a fuze for a projectile locked in a safe position as the projectile is fired from a gun until the 'acceleration'of the projectile has decreased sufficiently to permit translational and 0scillatory movement of a pair of detents from the initial locking position to the release position in which the inertia of the detents during such movement is employed to delay the arming of the projectile until'th'e projectile has safely cleared the gun.

Still another object is to provide new and improved means for maintaining the inertial'plunger of a fuze for a projectile locked in a safe position as the projectile is fired from a gun in which one end of each of a pair of locking detents is required to move both forwardly and reversely along the line of flight with respect to the projectile concurrently with translational movement of the detents until the detents have been moved to an unarmed position after the projectile has safely cleared the gun.

A still further object of the invention is to employ an oscillatory movement of a pair of detents in response to the setforward force applied thereto as the projectile strikes the target to lock the detents momentarily in the armed position for a period of time sufficient for the projectile to be fired by a percussion cap secured to an inertial plunger.

A still further object is to provide a new and improved device for delaying the arming of a projectile until the projectile is shot clear of the gun, which is economical to manufacture, reliable in operation and which possesses all of the desired qualities of ruggedness and durability.

Still other objects, advantages and improvements will be apparent from the following description, taken in connection with the accompanying drawings, of which:

Fig. 1 is a view in elevation and partially in section of a projectile employing the device of the present invention according to a preferred embodiment thereof;

Fig. .2 is an enlarged fragmentary sectional view taken along the line 22 of Fig. '1;

Fig. 3 is an enlarged fragmentary sectional view of one of the inertial locking detents pivoted by setback force applied thereto into engagement with the first 'retarding element employed therewith as the projectile travels through the gun;

Fig. 4 is a view similar to Fig. 3 but showing the inertial detent pivoted into engagement with the second retarding element "by centrifugal force applied thereto as the projectile travels along the trajectory;

Fig. 5 is a view of the inertial member pivoted into engagement with the third retarding element;

Fig. 6 is a view of the inertial de'tent moved outwardly to the armed position; and

Fig. 7 is a view of the inertial element pivoted into operative relation with the third retardation element by setforward force applied thereto as the projectile strikes the target.

Referring now to the drawings on which like numerals of reference are employed to designate like parts throughout the several views, and more particularly to Fig. 1 thereof, there is shown thereon a projectile indicated generally by the numeral 10 having an annular recessed portion 11 therein adapted to be engaged by a complementary portion of an explosive filled shell to which the projectile is secured, as is well known in the art to which the present invention pertains. The projectile is also provided with an annular sleeve 12 of material suitable for the purpose such, for example, as brass, adapted to be engaged by the rifling of the gun as the projectile is propelled outwardly therefrom by the firing of the explosive charge within the aforesaid shell and thereby impart a rotary movement to the projectile about the.

axis thereof as the projectile moves through the bore of the gun. The projectile is thus adapted to be propelled along a predetermined trajectory and to spin and rotate continuously through the trajectory.

The projectile comprises a shell 13, the forward end thereof having secured thereto in any suitable manner a nose 14 in which is preferably arranged the usual nose fuze 15. The shell 13 comprises a rear wall 16 integrally formed therewith in which a screw-threaded opening 17 is provided for receiving and supporting the base fuze generally indicated by the reference character 18. The base fuze comprises a housing 19 composed of any material suitable for the purpose, the forward end thereof being closed as at 21 for receiving and supporting the usual blockmember. 22. .Theblockmember is provided with a recess 23 in the forward end thereof having a booster charge 24 arrangedtherein, the booster charge being retained within the recess 23 by the flange member 25.

Secured to the member 22 as at 26 is a firing pin 27 such that the firing pin is in axial alignment with the projectile. The member 22 is provided with a pair of diametrically arranged apertures 28 within which is disposed a pair of inertial locking detents 29 adapted to be releasably maintained in engagement with the reduced cylindrical portion 30 of the firing pin by a pair of springs 31, the springs being arranged to urge the detents 29 yieldably and inwardly against the firing pin while permitting a small degree of pivotal or oscillatory move ment thereof as the detents move outwardly to the armed position. Each of the detents is recessed to receive the spring 31 and provided with a thickened base portion whereby the center of gravity of the inertial members is near the inner end thereof for a reason which will be more clearly apparent as the description proceeds.

A pair of cylindrical chambers 32 communicates inaligned relation with each of the apertures 28 respectively, the chambers being of sufiicient size to receive a sleeve 33 secured therein by a disc 34 having a reduced extension 35 thereon about which one end of the spring 31 is arranged. The discs are secured within the block member 22 in any suitable manner as by crimping at 36.

Each of the sleeves 33, it will be understood, is firmly clamped within the block member 22 by the disc 34 and is provided with a plurality of retardation members 37, 38 and 39 secured thereto and adapted to be engaged in succession by a flange 41 formed on the locking detent 29. The retardation members 37 and 39 are arranged in axial alignment with the sleeve member 33 and the retardation member 38 is disposed diametrically with respect to the members 37 and 39. The flange 41 is of sufficient size to prevent axial movement of the detent from the unarmed to the armed position thereof with engagement of the retardation members 37, 38 and 39 in successive order whereby the detent 29 is tilted or pivoted both forwardly and reversely by the retardation members during movement of the detent to the unlocked position in response to centrifugal force applied thereto. The sleeve 33 is preferably assembled within the block member 22 in such a manner that the retardation members 37 and 39 are forward and the member 38 is rearward during the flight of the projectile.

The detent 29 is formed with the cylindrical portion 42 thereof of sufiiciently less diameter than the aperture 28 as to permit free sliding and rocking movement of the inertial member within the aperture. Formed on the inertial detent 29 is a conical or tapered portion 43 and a second cylindrical portion 44 of lesser diameter than the cylindrical portion 42.

The fuze is also provided with a plunger 45 having secured in the forward end thereof a percussion cap 46 which is adapted to be moved forward integrally therewith by setforward force applied to the plunger and strike the firing pin with sutficient force to cause the cap to fire and thereby explode the booster charge within the projectile as the projectile strikes a target. The term setforward force as employed herein may be defined as the forwardly acting force applied to an element of the device as the projectile strikes the target.

The plunger is normally maintained in a safe position out of engagement with the detents 29 by a spring 47, Fig. 2, as is well known to those skilled in the art.

The percussion cap 46 is in communication with an explosive train 48 which is adapted to be completed as the plunger 45 moves to the firing position and thereby bring the percussion cap 46 into operative relation with respect to the booster charge 24. The explosive train 48 is normally discontinuous and comprises a first portion arranged within the inertia plunger supporting the percussion cap and movable therewith and a second fixed portion within the block member 22 as described more fully and claimed in my co-pending application for Delayed Arming Fuze for a Projectile, Serial No. 646,942, filed February 11, 1946.

With the inertial detents 29 in engagement with the cylindrical portion 30 of the firing pin, Fig. 2, the plunger 45 is locked in an initial safe position by reason of the cylindrical portion 43 of the detent being disposed within the path of travel of the plunger 45. The plunger 45 is locked by cylindrical portion 42 of the detent until the detent has moved to the unlocked position of Fig. 6.

The operation of the device will now be described with particular reference to Figs. 3 through 6 of the drawings. As the projectile moves forward within the bore of the gun in response to the explosion of the propelling charge, the inertial detent 29 moves outwardly away from the firing pin and pivots about the point 49 by the centrifugal and setback forces applied thereto respectively. The setback force at this time is sufficient to cause the detent 29 to be pivoted such that the flange 41 thereof engages the retardation member 37 on the forward part of the cylindrical sleeve 33, Fig. 3, thereby bringing the inertial detent 29 momentarily to rest until the setback force applied thereto has decreased sufliciently for the centrifugal force acting on the detent to cause the flange 41 thereof to be forced free of the retardation member 37 and brought into engagement with the retardation member 38, the detent 29 pivoting and moving outwardly to the position shown on Fig. 4 concurrently therewith.

The detent 29 remains at rest in the position of Fig. 4 momentarily until the inertia of the detent has been overcome by the cam action in the flange 41 with the retardation element 38. When this occurs the detent is V pivoted about point 51 and moves outwardly to the position shown on Fig. 5 with the flange 41 in engagement with and momentarily arrested by the retardation member 39, Fig. 5.

When the centrifugal force applied to the detent 29 has overcome in the inertia of the detent, the detent pivots about the point 49 and moves away from the retardation member 39 to the armed position shown on Fig. 6. Thefuze is now armed at a safe position of the projectile with respect to the gun from which it was fired.

The manner in which the detents are momentarily looked upon impact of the projectile with the target will best be understood by reference to Fig. 7 in which is shown the inertia detent 29 tilted forwardly by the setforward force applied thereto such that the flange 41 thereof is in engagement with the retardation member 39.

Whereas the preferred embodiment of the invention has been described with reference to the sleeve member 33 positioned such that the retardation members 37 and 39 thereof are arranged forwardly within the block member 22, it will be understood that the position of the sleeve member with respect to the block member is not critical and the device will operate satisfactorily regardless of the position of the sleeve member with respect to the block.

Briefly stated in summary, the delay in the arming of a fuze for a projectile in accordance with the present invention :is accomplished by the provision of a pair of locleingdetents which are arranged for pivotal and sliding movement within the tuze from an initial unarmed or locking position to an armed 'or unlocking position in which the aforesaid movement of the detents is controlled by a plurality of fixed motion retarding devices adapted to :be engaged alternately by the detent when a predetermined relation exists between the centrifugal and thesetback forces applied to the detent and in which the inertia .of the detent is employed to engage one of the motion retarding devices in response to the setterward force applied to the detent as the projectile strikes the target and thereby momentarily lock the detent in the armed position for a period of time suificient to insure firing of the projectile in response to the setforward force applied to the inertial plunger.

While the'invention has been described with particularity in regard to a specific example thereof which gives satisfactory results, it will 'be apparent to those skilled in the art to which the invention pertains, after understanding the invention, that the invention in its broader aspects could be carried out by other instrumentalities and it is intended, therefore, that the terms used in the claims are words of description and not of limitation except as necessitated by the prior art.

The inventiondescribed and claimed may be manufactured and used'by "or for the Government of the United States :of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed as new and desired to be secured by Letters "Patent 'of the United States is:

1. In a'projectile, acasing for said'projectile having'an explosive charge therein, a firing :pin :secured within the projectile, an inertial plunger slideably arranged within said projectile and having a'percussion cap secured therein, said percussion 'cap -being adapted to strike the firing pin and thereby explode the explosive charge as the projectile strikes a target, a pair of detents arranged within said projectile and adapted to be moved pivotally and translationally to an armed position by centrifugal force as the projectile rotates, a pair of flanged devices respectively formed on said detents, means for yieldably urging said detents into engagement with said firing pin for maintaining the plunger in a safe position until after the projectile has moved a predetermined distance beyond the muzzle of the gun, and a pair of annular retardation elements secured within said projectile through which the detents are adapted to be moved respectively, and a plurality of staggered retardation devices on said elements adapted to be engaged by said flanged devices in succession during movement of the detents to said armed position thereby to retard movement of the detents to the armed position until substantially the maximum velocity of the projectile has been attained.

2. In an arming device for a projectile having an explosive charge therein, a casing secured to one end of said projectile and extending interiorly therein for supporting said arming device, a firing pin secured within said casing, an inertial plunger slideably arranged within the casing and having a percussion cap secured therein, said percussion cap being adapted to strike the firing pin and thereby explode said explosive charge as the projectile strikes a target, a pair of detents pivotally and slideably arranged within said casing and adapted to lock the inertial plunger in a safe position until the detents have been moved to an armed position in response to rotative movement of the projectile as the projectile travels along a trajectory, means for yieldably urging said detents in locking position into engagement with said firing pin when the projectile is in a state of rest, a pair of flanges respectively formed on said detents, a pair of annular sleeve members respectively secured within said casing through which the detents are adapted to be moved respectively, and means on said sleeve members adapted to be engaged by said flange members as the projectile is set in motion along said trajectory thereby to cause the de- 6 tents tto oscillate and delay movement of -.the detents to said armed position until substantially the maximum velocity of the projectile has been attained.

3. In an arming device for a-projectile having an explosive charge therein,a casing secured'to one end of said projectile for supporting said arming device therein, a firingpin secured within said casing, an inertial plunger slideably arranged within the casing and having a percussion cap secured therein, said percussion cap being adapted to strike .thefiring pin and thereby explode said explosive charge as the projectile strikes a target, a pair of hollow detents arranged within said casingand adapted to be moved translationally and pivotally from an unarmed position to an armed position by setback and centrifugal forces applied thereto as the projectile is .fired .from a. gun, a pair of springs respectively arranged in said hollow detents for yieldably urging the detents into engagement with said firing pin thereby to initially lock the inertial plunger in said unarmed position, means secured to said casing for applying a predetermined pressure to said springs, a pairof sleeve members secured within said casing and adapted to enclose a portion of the detents as the detents are moved .from the unarmed position to said armed position, a plurality of retardation members formed within each of said sleeve members, and a pair of .flanges respectively formed on said detents of sufiicient size to insure engagement of the flange members with the retardation members during movement of the detents from said unarmed position to said armed position thereby to delay for a predetermined period of time said movement of the detents to the armed position in response to centrifugal force applied thereto as the projectile rotates during travel of the projectile along a trajectory.

4. In an arming device for a projectile having an explosive charge therein, a casing secured to one end of said projectile and extending interior'ly therein for supporting said arming device, a firing pin secured within said casing, an inertial plunger slideably arranged within said casing and having a percussion cap secured therein, said percussion cap being adapted to strike the firing pin and explode said explosive charge as the projectile strikes the target, a pair of inertial detents arranged within said casing and adapted to be moved translationally and pivotally from an initial unarmed position to an armed position by setback and centrifugal forces applied thereto as the projectile rotates, means for yieldably urging said detents into engagement with said firing pin to initially lock the inertial plunger in an unarmed position, means secured to said casing for applying a predetermined pressure to said yieldable means, a pair of sleeve members respectively secured within said casing and having a plurality of staggered retardation members formed therein, a pair of flanges formed on said detents respectively and adapted to engage said retardation members in successive order thereby to delay said movement of the detents to the armed position, each of said flanges being adapted to engage one of said retardation members in each of the sleeve members respectively in response to the setforward force applied to the detents as the projectile strikes the target and thereby momentarily lock the detents in said armed position for a period of time sulficient for the projectile to be fired by said percussion cap.

5. In an arming device for a projectile, the combination of arming and firing means including a percussion cap adapted to be moved by inertia from an initial safe position to a firing position as the projectile strikes a target, a firing pin secured to said device for firing said cap as the firing means moves to said firing position, a pair of inertial detents slideably arranged within the path of travel of said firing means and adapted to be moved from an initial locking position to an armed position out of said path of travel by centrifugal force applied thereto as the projectile rotates during travel along a trajectory, a pair of annular members secured within said projectile through which the detents are adapted to move respectively, flanged means including a plurality of staggered lugs on said annular members for causing said detents to oscillate during movement to said armed position thereby to retard said movement for a predetermined period of time, and means on said detents responsive to the setback force applied thereto for causing the detents to engage the first one of said staggered lugs as the detents move outwardly by centrifugal force during the travel of said projectile through the bore of a gun.

'6. In an arming device for a projectile, the combination of arming and firing means including a percussion cap adapted to be moved by inertia from an initial safe position to a firing position as the projectile strikes a target, a firing pin secured to said device for firing said cap as the firing means moves to said firing position, a pair of inertial detents slideably arranged Within the path of travel of said firing means and adapted to oscillate during movement from an initial locked position to an armed position out of the path of travel of said firing means, a pair of annular members respectively secured within said projectile through which the detents are adapted to move respectively, a plurality of devices respectively formed in staggered relation within said annularmembers and adapted to be engaged in succession by said detents for causing the detents to oscillate and thereby retard the movement thereof from said initial locked position to the armed position, means responsive to the setback force applied to the detents for causing 'the detents to engage the first one of said staggered devices as the detents move outwardly by centrifugal force while the projectile is passing through the bore of a gun, and means on said detents for causing the detents to engage in succession the other staggered devices on each of said annular members respectively as the detents move outwardly from said initial locked position to the armed position.

7. In an arming device for a projectile having an explosive charge therein, a casing secured to one end of the projectile for supporting said arming device, a pair of annular detents yieldably supported Within the casing for movement translationally and pivotally from an unarmed position to an armed position by setback and centrifugal forces applied thereto as the projectile is fired from a gun, a pair of flanges respectively arranged on said detents, means including a pair of resilient members respectively arranged Within said annular detents for yieldably supporting the detents, a pair of sleeve devices secured to the casing in alignment with said detents for enclosing a portion of the detents as the detents move from the unarmed position to said armed position, a plurality of lugs respectively arranged on said sleeve devices for engagement with said flanges as the projectile is set in motion along a trajectory for causing the detents to oscillate and thereby delay movement thereof to said armed position until substantially the maximum velocity of the projectile has been attained, and means including a firing pin and an inertia responsive element initially locked against movement by said detents for firing said charge when the detents have been moved to said armed position and upon impact of the projectile with a target.

References Cited in the file of this patent UNITED STATES PATENTS 1,216,802 Hawkins Feb. 20, 1917 1,383,751 Pillars July 5, 1921 1,552,435 Johnson -Sept. 8, 1925 FOREIGN PATENTS 304,246 Germany Sept. 28, 1920 489,020 Great Britain Oct. 15, 1936 

